Unity - The multiplatform game creation tools for everyone.
Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Online Alarm Kur - Free online alarm clock, set alarm easily on your computer using the internet alarm clock without downloading any software, wake up in time with the loud online alarm clock.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
KukuKlok - Kukuklok is a free alarm clock available online and offline.